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Proceedings Paper

Start-up of lasing in compact far-infrared free-electron laser driven by 8-MeV microtron
Author(s): Grigori M. Kazakevitch; Young Uk Jeong; ByungCheol Lee; Sung Oh Cho; Sun Kook Kim; Jongmin Lee
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Paper Abstract

We have developed a compact Far Infrared Free Electron Laser (FIR FEL) on the base of 8 MEV microtron, which can provide 6 microsecond(s) up to 70 mA macropulse beam current. Beam line consists of bending and steering magnets. Optical Transition Radiation screen and 3 doublets of quadruples to provide matching of microtron output electron beam parameters with optimized parameters for FEL operation. A 2 m length, 25 mm period and 5.7 mm gap undulator has extremely low field error of 0.05% for the magnet field peak amplitude in the range 5.5 - 6.5 kG. Inside the undulator the electron beam passes through 2 mm X 20 mm aperture 2779 mm length planar waveguide. On both sides of the waveguide are installed two cylindrical 3 m curvature mirrors. They form confocal type free space mode in horizontal plane and waveguide mode in vertical plane of the optical resonator. A hole in output mirror provides coupling ratio about 1 - 2%. During experiments we have observed the coherent effect in spontaneous emission with power enhancement approximately 1000 times. It was observed too the long wave radiation, which can be explained by vertical betatron oscillation of electrons in undulator. The experiments with FIR resonator and Ge-Ga liquid He cooled detector shown coherent generation and tunability of it power with tuning of the length of the resonator. The enhancement of outcoupled signal in 50 times was detected with changing of resonator length. This phenomenon can be explained as startup of the lasing process in FIR resonator.

Paper Details

Date Published: 25 October 1999
PDF: 6 pages
Proc. SPIE 3775, Accelerator-based Sources of Infrared and Spectroscopic Applications, (25 October 1999); doi: 10.1117/12.366646
Show Author Affiliations
Grigori M. Kazakevitch, Budker Institute of Nuclear Physics (South Korea)
Young Uk Jeong, Korea Atomic Energy Research Institute (South Korea)
ByungCheol Lee, Korea Atomic Energy Research Institute (South Korea)
Sung Oh Cho, Korea Atomic Energy Research Institute (South Korea)
Sun Kook Kim, Korea Atomic Energy Research Institute (South Korea)
Jongmin Lee, Korea Atomic Energy Research Institute (South Korea)


Published in SPIE Proceedings Vol. 3775:
Accelerator-based Sources of Infrared and Spectroscopic Applications
G. Lawrence Carr; Paul Dumas, Editor(s)

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